**2. Agriculture and global food security**

Food security has always been a major concern for human civilizations throughout the history [17]. In 1974 World Food Summit, food security was defined as for the first time: "availability at all times of adequate world food supplies of basic foodstuffs to sustain a steady expansion of food consumption and to offset fluctuations in production and prices" [18]. From time to time the definitions have been modified. "Food security, as defined by the United Nations' Committee on World Food Security, means that all people, at all times, have physical, social, and economic access to sufficient, safe, and nutritious food that meets their food preferences and dietary needs for an active and healthy life". Concerns regarding the global food security and production have grown in recent decades. Climate change, population growth, rising food prices, and environmental stresses will all have substantial effects on food security in the future decades. Adaptation techniques and policy responses to global change are urgently needed, including alternatives for managing water allocation, land use patterns, food trade, postharvest food processing, food prices, and food safety. Furthermore, in developing countries, changing lifestyles and diets have impacted the demand for meat and dairy products [19]. Increasing demand for the food will inevitably increase land competition, food security and availability remains one of the most pressing issues on the public agenda [20]. The agriculture sector's challenge is no longer merely to maximize output and feed 9 billion people without large increases in food prices until 2050, but also to ensure food availability, distribution, and social justice for all people.
